A Technical Review and Fact-Check: The Rolsky & Kelkar (2021) Study on Polyvinyl Alcohol (PVA) and its Inapplicability to Water-Soluble Detergent Films

In short:

• The SciPinion panel of experts found that the Rolsky and Kelkar paper contains significant scientific flaws. Given the high degree of consensus amongst the panel of experts, SciPinion concludes that the Rolsky and Kelkar (2021) paper should not be given much credibility for informing the degradation of PVA in the real world and therefore insufficient for consideration when informing science-based regulatory decisions.

• The EPA, prompted by an application to re-assess PVAs environmental impact based in major part by the Rolsky paper, also rejected the conclusions of the Rolsky paper, citing a result of a “cursory study”, the EPA found many references which contradict the conclusions of the Rolsky paper, and that paper ignored many of the well established scientific techniques for assessing environmental fate. PVA remains on the EPA Safer Choice List.

• In addition, multiple independent expert panels and regulatory bodies, including the U.S. EPA and the European Chemicals Agency (ECHA), have confirmed that detergent grades of water-soluble PVA are, by definition, not a microplastic and degrade during water waster treatment end environmental processes.

• The Rolsky and Kelkar paper is a single study, based on an unvalidated model with insufficient data input, from the much broader range of data available, and makes unsubstantiated claims by scientifically inaccurate extrapolation. Subsequent published and peer reviewed data across solubility and biodegradability further negate the conclusions in the paper.

Executive Summary:

A 2021 modeling study by Rolsky & Kelkar claimed that approximately 75% of the polyvinyl alcohol (PVA) from detergent pods persists in the environment, suggesting it is a significant source of pollution. This claim has been widely cited despite containing significant scientific flaws. Its conclusions were rejected by an independent scientific peer review company, SCIPINION. They stated : “The experts found that Rolsky and Kelkar’s approach had significant flaws. The experts concluded the actual degradation of PVA in the real world will be much higher than predicted by the Rolsky and Kelkar model. There was a clear consensus amongst the panel of experts that PVA should be considered readily biodegradable ..(and).. that PVA should be largely removed by wastewater treatment plants and therefore should not build up in the environment.”

The Rolsky and Kelkar paper was also used as the central basis for a petition to the U.S. Environmental Protection Agency (EPA) that questioned PVA’s Safer Choice classification, its environmental fate and safety profile.

The EPA rejected the petition in April 2023, and concluded that detergent-grade PVA is a water-soluble, biodegradable polymer that does not contribute to microplastic pollution. And reaffirmed its Safer Choice classification.

SCIPINION recruited a panel of eight (out of over 160 applicants), who are globally recognized as experts in biodegradation and modeling of degradation processes in wastewater treatment plants. All eight have a doctoral degree, with two from the United States, four from European countries, one from the African continent, and one from Southeast Asia. The expert panel has a combined 196 years of experience and 1,886 publications.

The SciPinion panel of experts found that the Rolsky and Kelkar paper contains significant scientific flaws.

The panel concluded the Rolksy et al paper conclusions are invalid due to several fundamental flaws, which led to an overall positive assessment of detergent grade PVA.

Specifically:

1. Incorrect assumptions and the modelling used. Experts gave the Rolsky study a low-medium rating of 3.9 out of 10 with major flaws in the assumptions and modeling used.

2. Incorrect scaling from lab tests to real world biodegradability: Experts noted that the study did not use guidance on how to scale degradation rates from laboratory-based studies to modeling of full-scale biodegradation wastewater treatment plants. Actual biodegradation is much higher than predicted by Rolsky.

3. A mismatch of data comparison and references with different grades of PVA. In addition, no actual tests were conducted specifically for the paper.

4. A clear majority of the panelists (6/8) believe that actual biodegradation would be higher or much higher than predicted by Rolsky and Kelkar.

5. Panelists came to a near consensus (7/8) that PVA should receive a “pass” grade as biodegradable following both US EPA and European Union guidance. A “pass” is considered by regulatory agencies to indicate that a compound will be effectively removed in wastewater treatment plants.

1.0 Introduction

A 2021 modeling study by Rolsky & Kelkar, "Degradation of Polyvinyl Alcohol in US Wastewater Treatment Plants and Subsequent Environmental Fate," received significant media attention for its claim that a substantial majority (~75%) of the polyvinyl alcohol (PVA) from sources like detergent pacs passes through wastewater treatment facilities untreated. This claim has been used to suggest that water-soluble PVA films are a source of pollution. However, a detailed technical review of the study, conducted by independent scientific bodies and regulatory agencies, has found its conclusions to be inapplicable to the types of water-soluble PVA used in detergent products. This review will analyze the specific technical flaws in the Rolsky & Kelkar study, present the rebuttals from authoritative bodies, and clarify the established scientific consensus on the environmental fate of water-soluble PVA.

2.0 Observations on the Rolsky paper

2.1 Data sources and PVA grades

The Rolsky and Kelkar (2021) study used data from a variety of sources, employing varying grades of PVA and compositions of PVA in combination with other chemistries, to make conclusions for only one specific grade: the one used in water-soluble films and pods. Their paper admits that the type of PVA used in detergent pods is very specific but then uses studies covering multiple PVA grades, as well as studies involving PVA mixtures or specific treatments like irradiation completely unrelated to detergent-grade PVA, to make its conclusions.

This is analogous to stating sugar does not dissolve by referencing the entire range of chemistries in the sugar family, from insoluble starches to soluble table sugar. It is well-known that PVA is available in different grades, characterized by a feature known as the degree of hydrolysis, which dictates its solubility (Finch, 1972). Degree of hydrolysis dictates PVA’s solubility- from being insoluble at 20C/68F, to grades which are very soluble at 20C/68F. Insoluble grades are used in construction and textiles, while the soluble form is used in detergent pods. By mixing data from these different chemistries, Rolsky and Kelkar’s conclusions about detergent-grade PVA must be considered invalid.

2.2 Methodological Analysis of the Rolsky & Kelkar (2021) Study

The invalidity of the study's conclusions stems from critical errors in its foundational assumptions and methodology.

• Modeling vs. Empirical Measurement: The Rolsky & Kelkar study is a literature-based modeling exercise. It did not generate any new empirical data.

• The authors aggregated parameters from pre-existing literature-- some decades old and before water-soluble PVA pods were sold—to create a model estimating detergent grade PVA fate. In many cases this data was taken using PVA data from studies before water soluble PVA pods were sold i.e the PVA used in the studies cannot have been detergent pod grade PVA.

• Reported Mathematical Discrepancies: An independent peer review of the study, conducted by the expert panel at SciPinion, identified a potential mathematical error in the study's concentration modeling. The panel noted that the model appeared to miscalculate flow and dilution factors, potentially resulting in a final environmental concentration estimate that was incorrect by several orders of magnitude (SciPinion LLC, 2024).

2.3 Biodegradability assessment

The study used decade-old data from a variety of different studies on PVA and PVA-containing compositions (for example, some conclusions in the text are based on studies on textile PVA) to apply to detergent-grade PVA. This is an incorrect extrapolation of data from materials designed to behave differently, with different solubilities and degradation profiles dependent on their use. Despite this, the supplemental material in the paper lists a series of studies demonstrating that PVA biodegradability averages about 80% in lab-simulated studies. Such a result in simulation tests is well-known to be predictive of biodegradability in the real world and indicate PVA is material class that can biodegrade in the environment. These studies are conservative, overestimating test material and underestimating degrading microbes by a factor of about 20,000. This high average number for the biodegradability of PVA materials is ignored in the main body of the paper.

3.0 Current Scientific Consensus on PVA Biodegradability

Several studies since the Rolsky and Kelkar article have concluded detergent grade PVA is biodegradable. Studies have been conducted on films (Byrne et al 2021) and also on the PVA chemistry itself. All report a positive biodegradability assessment. These are studies under the internationally recognized OECD protocols (OECD301, 302 and 309). These protocols have a long pedigree and are the basis for assessing the environmental fate of materials. Multiple studies have concluded they are predictive of fate in the real world, and results above 60% biodegradation in the lab, predict biodegradability in the real world.

These studies conclude detergent grades of water soluble PVA is biodegradable and will not persist in the environment. These studies show that detergent grade PVA will also biodegrade in river water. (Menzies at al 2023; McDonough et al 2023)

These studies also indicate detergent grade PVA biodegradability is widespread and can be achieved by a wide variety of degraders found in a wide variety of waste water treatment plants. Similar (high) biodegradation results were across bugs taken from waste water treatment plants across the US and globally. (McDonough et al 2023)

Finally, studies using a simulated wastewater treatment plant set-up showed also high biodegradability for detergent grade PVA. (McDonough et al 2024)

4. Rebuttal of Claims based on the Rolsky Paper

4.1 There is overwhelming scientific evidence that detergent grade PVA does not create microplastics

The Rolsky and Kelkar paper attempts to link detergent grade PVA to reported issues across many years on the increase in microplastics found in the environment, and health effects. However, no evidence is given anywhere in the paper that detergent grade PVA is a microplastic. The papers cited by Rolsky and Kelkar refer either generically to microplastics, or to specific known microplastics like polyvinyl chloride, polystyrene, polyamides. There is NO mention of detergent grade PVA in these cited papers.

Rolsky and Kelkar attempt to link microplastic behaviors like the adsorption of organics or pharmaceuticals to detergent-grade PVA, but no evidence is presented. Such an adsorption mechanism requires PVA to be undissolved in water- a property that detergent grade PVA does not have. It is fully soluble, a fact acknowledged in the Rolsky paper. PVA’s solubility is demonstrated by many studies looking at the molecular structure of PVA in water using NMR, X ray scattering, end other high resolution analytical techniques. All conclude detergent grade PVA will be surrounded by water molecules, and not bind to itself. This is the definition of dissolution or solubility-when the solid ingredient is put in water, its discrete molecules will be completely surrounded by water. (Bao et al 2002; Budhlall et at 2003) More recent studies on detergent grade PVA using Xray scattering and Atomic force microscopy, comparing vs a known microplastic such as polystyrene, conclude the same-- detergent grade PVA is fully soluble and cannot form hard particles at nano-or micro-scale. (Agostiniano et al 2025, P&G C&D blog 2025, CRIS podcast 2025)

A comparison of the properties of micro and nano-plastics as compared to PVA and other water soluble polymers used in Cascade and Tide PVA can be found on https://cascadeclean.com/en-us/about-cascade/pva-smart-film/. This cites over 30 references comparing the properties and behaviours of known microplastics (from solubility to persistence to toxicity), and shows detergent grade PVA has none of them.

4.2 Safety assessment of PVA

The paper attempts to conclude that because their model predicts large amounts of PVA in the environment, this is somehow "unsafe." Yet the paper’s supplemental material has a specific section on PVA safety, listing references confirming PVA has been studied many times and assessed as safe for humans. It states the use of PVA has been thoroughly investigated due to the fact it is used widely as a coating agent for the dietary and pharmaceutical industries. It acknowledges that even the studies which show minor effects at very high levels of PVA that such situations for humans are “..not possible under any imaginable scenario, PVA by itself would not be toxic to humans” (Demeris et al 2003; Nair et al 1998, European Food Safety Authority ESFA (2006) are all cited in the supplemental by the Rolsky paper to demonstrate the safe use of PVA. The EPA (2023) assessment also concludes the same safety profile of detergent grade PVA, as does a recent article by CRIS (2025).

4.3 Irrelevance of Plasticizer Concerns

The paper states concerns about plasticizers used in microplastics. However, in the supplemental text, it acknowledges that such additives are not found in PVA detergent films: "While additives of PVA have been documented previously, none of the published information on the additives themselves suggest that are at all toxic, mutagenic or carcinogenic."

4.4 Biodegradation Pathways

The Rolsky and Kelkar paper in the main text state a possible byproduct of PVA degradation is Polyethylene. There is no such literature basis for such a claim in waste water treatment plant processes. PVA degradation pathways have been studies, and a typical process is fragmentation of the PVA polymer chain into smaller and smaller fragments, via fatty acids and ketones. Ultimately ending up in carbon dioxide, water, or being absorbed by the degrading degrades as biomass – in the same way human digestion yields carbon dioxide, water and chemistries to enable energy and/or use in cell repair or metabolic process (or in worst case, weight increase !).

5.0 Regulatory and Scientific Consensus on Water-Soluble PVA

The consensus among independent expert and regulatory bodies, which is based on decades of empirical data, directly contradicts the conclusions of the Rolsky & Kelkar model.

5.1 U.S. Environmental Protection Agency (EPA):

In April 2023, the EPA formally denied a petition to regulate PVA as a harmful substance. The agency, referencing its own extensive data and the OECD 301B standard, concluded that the petition—which relied heavily on the Rolsky study—"failed to provide reliable evidence" and "did not present a scientifically sound basis" to reverse the EPA's long-standing position that water-soluble PVA is safe and biodegrades effectively (U.S. EPA, 2023).

5.2 SciPinion Independent Expert Panel:

In 2024, a panel of eight independent scientists specializing in polymer science, biodegradation, and wastewater treatment conducted a formal review of the Rolsky & Kelkar study. The panel gave the study a low "Credibility Score" of 3.9 out of 10, concluding it contained "significant scientific flaws" and that its findings were "not defensible" due to the lack of experimental validation and the critical material mismatch error (SciPinion LLC, 2024).

6.0 The Definition of a Microplastic

The European Chemicals Agency (ECHA) define microplastics as solid, water-insoluble plastic particles. This is now enshrined in regulation in Europe. This is based on years of research by European Chemicals Hazard Agency (ECHA) and also many published papers, most significantly Hartmann et al (2019). This paper and the ECHA definition rely on the physical properties of materials that give rise to affects seen by microplastics: use of toxic plasticizers, persistence in the environment, solid edges (hence insoluble in water) to adsorb toxic contaminants. None of these are true to detergent grade soluble PVA. In the US, no such defined regulatory definition exhibits, but multiple regulatory references including the EPA, National Ocean Service, California’s microplastic drinking water definition, and the University of Maine’s “Senator Geroge I Mitchel Centre for Sustainability studies” use words such as “particles”, “pieces”; “bits”, “fragments”, “solid interface”. Because the PVA used in detergent films is, by design, a water-soluble polymer, it does not meet the scientific or available regulatory definitions – it does not have the behavioral characteristics of well know microplastics. Rather it has the behavioral characteristics of common water-soluble polymers used widely in industrial, medical, and agricultural applications (ACI, 2025). And once dissolved, it exists as individual polymer chains in the water, which are then available for microbial consumption, unlike insoluble plastic fragments.

7.0 The Primary Source of Microplastic Pollution from Laundry: Synthetic Fiber Shedding

While water-soluble polymers like PVA are designed to biodegrade, scientific consensus confirms that the most significant source of microplastic pollution from the laundry process is the shedding of microscopic fibers from synthetic textiles (Kelly et al., 2019).

Fabrics such as polyester, nylon, and acrylic are forms of plastic. During the mechanical action of the wash cycle, these textiles shed millions of tiny, insoluble plastic fibers. These solid particles then enter the wastewater stream, and many are too small to be fully captured by treatment plants. Research has shown that wash conditions significantly impact the quantity of fibers shed (Kelly et al., 2019). The most effective consumer interventions to reduce this form of pollution are washing in colder, quicker cycles and washing fuller loads, which reduces the mechanical abrasion that causes fibers to break off (Cotton et al., 2020).

Studies looking for PVA particles from washing machines or dishwashers have found no evidence of them, which is expected since detergent-grade PVA is soluble and cannot exist as a particle once dissolved (Bayo et al., 2022; Sol et al., 2023).

8.0 Conclusion

The claim that PVA from detergent pods persists in the environment is based on a flawed modeling study that has been scientifically invalidated by expert panels and rejected by regulatory authorities like the U.S. EPA. The scientific consensus, supported by decades of empirical research and regulatory precedent and more recent in-depth studies, is that the specific, water-soluble grades of PVA used in detergents dissolve completely and degrade effectively in wastewater treatment. Overwhelming scientific evidence demonstrates that it is not a microplastic. Detergent grade PVA has also been evaluated as safe, including for multiple medical applications. Consumers concerned about microplastic pollution from laundry should focus on the scientifically-verified primary source: the shedding of fibers from synthetic clothing.